You will be able to create and find Doantions on your Merchant Manager in your owner dashboard. 

https://manage.joe.coffee/marketing/donations

Step #1: Go to your marketing tab 

Step #2: Go to your donations tab 

Step #3: Create a name for your donation 

Step #4: Select the time frame you'd like to donation to be live for. 

Just for you information in the first iteration of the donations feature will prompt the barista screen.